Improvement in pulmonary function and elastic recoil after lung-reduction surgery for diffuse emphysema

Evaluation of bronchoscopic lung volume reduction coil treatment results in patients with severe emphysema

INTRODUCTION

Bronchoscopic lung volume reduction coil (BLVR-C) implantation is an alternative therapeutic approach that can be applied together with medical treatment for patients with severe emphysema. BLVR-C is both easier and safer in terms of complications than volume reduction surgery. This study aimed to evaluate medium-term outcomes following BLVR-C treatment.

METHODS

Forty patients who underwent BLVR-C between September 2013 and March 2014 were reviewed retrospectively. We compared changes between the baseline and 6-month post-procedural results with respect to pulmonary function tests, a 6-min walk test (6MWT), chronic obstructive pulmonary disease (COPD) assessment test (CAT), St. George's Respiratory Questionnaire (SGRQ), and pulmonary artery pressure (PAP) and arterial blood gas analyses. Secondary outcomes included procedure-related and follow-up complications.

RESULTS

An average of 9.5 (range: 5-11) coils were placed per lung in an average procedural duration of 20.8 ± 7.0 min (range: 9-45) min. Six months after BLVR-C treatment, significant improvements were observed in patients' pulmonary function tests and quality of life. Changes were observed in the forced exhalation volume in 1 s (+150 mL), residual volume (-14.5%), 6MWT (+48 m), SGRQ (-10.5) and CAT Score (-7.5). Changes in the PAP and partial pressure of carbon dioxide values were not significant, and pneumothorax did not occur. In a 6-month follow-up, 11 cases of COPD exacerbation (41.4%), 7 cases of pneumonia (16.9%) and 1 death (2%) occurred. Treatment in 1 case was postponed because of hypotension and bradycardia during the process.

CONCLUSION

BLVR-C treatment appears to be effective over the medium-term and safe for patients with severe emphysema.

Assessment of volume reduction effect after lung lobectomy for cancer

BACKGROUND

Lung lobectomy results in an unexpected improvement of the remaining lung function in some patients with moderate-to-severe emphysema. Because the lung function is the main limiting factor for therapeutic decision making in patients with lung cancer, it may be advantageous to identify patients who may benefit from the volume reduction effect, particularly those with a poor functional reserve.

METHODS

We measured the regional distribution of the emphysematous lung and normal lung using quantitative computed tomography in 84 patients undergoing lung lobectomy for cancer between January 2010 and December 2012. The volume reduction effect was diagnosed using a combination of radiologic and spirometric parameters.

RESULTS

Eight patients (10%) were favorably affected by the volume reduction effect. The forced expiratory volume in one second increased postoperatively in these eight patients, whereas the forced vital capacity was unchanged, thus resulting in an improvement of the airflow obstruction postoperatively. This improvement was not due to a compensatory expansion of the remaining lung but was associated with a relative decrease in the forced end-expiratory lung volume. According to a multivariate analysis, airflow obstruction and the forced end-expiratory lung volume were independent predictors of the volume reduction effect.

CONCLUSIONS

A combined assessment using spirometry and quantitative computed tomography helped to characterize the respiratory dynamics underlying the volume reduction effect, thus leading to the identification of novel predictors of a volume reduction effect after lobectomy for cancer. Verification of our results by a large-scale prospective study may help to extend the indications for lobectomy in patients with oncologically resectable lung cancer who have a marginal pulmonary function.

Chronic obstructive pulmonary disease

COPD is characterized by airflow limitation that is not fully reversible. The morphological basis for airflow obstruction results from a varying combination of obstructive changes in peripheral conducting airways and destructive changes in respiratory bronchioles, alveolar ducts, and alveoli. A reduction of vascularity within the alveolar septa has been reported in emphysema. Typical physiological changes reflect these structural abnormalities. Spirometry documents airflow obstruction when the FEV1/FVC ratio is reduced below the lower limit of normality, although in early disease stages FEV1 and airway conductance are not affected. Current guidelines recommend testing for bronchoreversibility at least once and the postbronchodilator FEV1/FVC be used for COPD diagnosis; the nature of bronchodilator response remains controversial, however. One major functional consequence of altered lung mechanics is lung hyperinflation. FRC may increase as a result of static or dynamic mechanisms, or both. The link between dynamic lung hyperinflation and expiratory flow limitation during tidal breathing has been demonstrated. Hyperinflation may increase the load on inspiratory muscles, with resulting length adaptation of diaphragm. Reduction of exercise tolerance is frequently noted, with compelling evidence that breathlessness and altered lung mechanics play a major role. Lung function measurements have been traditionally used as prognostic indices and to monitor disease progression; FEV1 has been most widely used. An increase in FVC is also considered as proof of bronchodilatation. Decades of work has provided insight into the histological, functional, and biological features of COPD. This has provided a clearer understanding of important pathobiological processes and has provided additional therapeutic options.

Endoscopic lung volume reduction with endobronchial valves in patients with severe emphysema and established pulmonary hypertension

BACKGROUND

One of the most common forms of pulmonary hypertension (PH) is that associated with chronic obstructive pulmonary disease (COPD). So far, patients with severe emphysema and established PH have been excluded from endoscopic lung volume reduction (ELVR) therapy due to the risk of right heart decompensation.

OBJECTIVE

The aim of this pilot study was to evaluate the feasibility and efficacy of ELVR using one-way endobronchial valves (EBV) in this specific group of patients.

METHODS

We prospectively included 6 patients with COPD, severe heterogeneous emphysema, and established PH who underwent right heart catheterization and clinical assessments before and 90 days after ELVR with unilateral EBV placement.

RESULTS

This study was not powered to measure any statistical differences in endpoints. Ninety days after ELVR, the symptoms, lung function, and hemodynamics improved in 5 out of 6 patients (1 patient normalized and 1 slightly worsened). The mean hemodynamics improved from baseline to 90 days after ELVR as follows: mean pulmonary artery pressure, -2.5 ± 3.5 mm Hg; pulmonary arterial wedge pressure, -4.3 ± 8.3 mm Hg; cardiac index, +0.3 ± 0.6 l/min/m(2), and 6-min walk distance, +59 ± 99 m. ELVR was performed without PH-related complications in all patients.

CONCLUSION

To our knowledge, this is the first prospective, single-center pilot study to evaluate the feasibility and efficacy of ELVR in patients with established PH. ELVR was feasible and resulted in an improvement of clinical and hemodynamic parameters in 5 out of 6 patients. These results have to be further confirmed in larger-scale controlled studies.

Cardiopulmonary coupling in chronic obstructive pulmonary disease: the role of imaging

Chronic obstructive pulmonary disorder (COPD) is a systemic disease that affects the cardiovascular system through multiple pathways. Pulmonary hypertension, ventricular dysfunction, and atherosclerosis are associated with smoking and COPD, causing significant morbidity and poor prognosis. Coupling between the pulmonary and cardiovascular system involves mechanical interdependence and inflammatory pathways that potentially affect the entire circulation. Although treatments specific for COPD-related cardiovascular and pulmonary vascular disease are limited, early diagnosis, study of pathophysiology, and monitoring the effects of treatment are enhanced with improved imaging techniques. In this article, we review recent advancements in the imaging of the vasculature and the heart in patients with COPD. We also explore the potential mechanism of coupling between the progression of COPD and vascular disease. Imaging methods reviewed include specific implementations of computed tomography, magnetic resonance imaging, dual-energy computed tomography, positron emission tomography, and echocardiography. Specific applications to the proximal and distal pulmonary vasculature, as well as to the heart and systemic circulation, are also discussed.

Noninvasive ventilation and lung volume reduction

As parenchymal lung disease in chronic obstructive pulmonary disease becomes increasingly severe there is a diminishing prospect of drug therapies conferring clinically useful benefit. Lung volume reduction surgery is effective in patients with heterogenous upper zone emphysema and reduced exercise tolerance, and is probably underused. Rapid progress is being made in nonsurgical approaches to lung volume reduction, but use outside specialized centers cannot be recommended presently. Noninvasive ventilation given to patients with acute hypercapnic exacerbation of chronic obstructive pulmonary disease reduces mortality and morbidity, but the place of chronic non-invasive ventilatory support remains more controversial.

Effectiveness of endobronchial coil treatment for lung volume reduction in patients with severe heterogeneous emphysema and bilateral incomplete fissures: a six-month follow-up

BACKGROUND

Treatment with lung volume reduction coils (LVRC) may be effective in patients with severe heterogeneous emphysema and incomplete fissures.

OBJECTIVE

We hypothesized that LVRC placement improves pulmonary function, exercise tolerance and quality of life in these patients.

METHODS

Twenty-six patients with chronic obstructive pulmonary disease (COPD), 13 males and 13 females, aged 66 ± 8 years with heterogeneous emphysema and incomplete fissures were included in this retrospective analysis. The coils were implanted unilaterally in the upper or lower lobe. Patients were followed up at 30, 90 and 180 days after treatment and changes in pulmonary function test and 6-minute-walk-test (6MWT) values as well as scores for the modified Medical Research Council (mMRC) dyspnea scale and the St. George's Respiratory Questionnaire (SGRQ) were recorded.

RESULTS

FEV1 improved significantly at 90 days and tended to decrease at the 180-day follow-up (0.67 ± 0.17 vs. 0.78 ± 0.25 vs. 0.73 ± 0.21 liters, respectively, p < 0.001). The 6MWT score had improved significantly at 90 days and had tended to decrease at the 180-day follow-up (216 ± 107 vs. 262 ± 97 vs. 262 ± 112 m, respectively, p = 0.001). SGRQ was significantly improved at 90 days. Multivariate analysis showed that worse 6MWT performance at baseline was independently associated with a greater improvement in 6MWT at the 90-day follow-up. The total complication rate was 54% (n = 14) and included light hemorrhage in 6 patients, COPD exacerbation in 6, pneumothorax in 1 and both COPD exacerbation and pneumothorax in 1 patient.

CONCLUSIONS

This is the first study to show that LVRC in patients with heterogeneous emphysema and incomplete fissures improves exercise capacity, quality of life and lung function up to 90 days after the intervention. Further studies are needed to assess the long-term effects of LVRC in these patients.

Simultaneous assessment of airway instability and respiratory dynamics with low-dose 4D-CT in chronic obstructive pulmonary disease: a technical note

BACKGROUND

Advanced-stage chronic obstructive pulmonary disease (COPD) is associated with severely altered respiratory dynamics. Dynamic airway instability is usually diagnosed by invasive bronchoscopy. Cine-computed tomography (CT) may be used alternatively, but is limited to predefined anatomical positions. Also, a paradoxical diaphragmatic motion has been described in patients with emphysema.

OBJECTIVES

As the airways and chest wall show inherently high contrast to airway lumen and lung tissue, low-dose CT acquisitions potentially suffice for depicting tracheobronchial and chest wall motion. Therefore, we propose low-dose dynamic respiratory-gated multidetector CT (4D-CT) of the whole chest as a new method to assess respiratory dynamics.

METHODS

4D-CT was performed in 3 patients (52, 62 and 76 years old) with suspected tracheal instability due to COPD or tracheal stenosis at minimal pitch (0.09) and radiation exposure (1.4-1.9 mSv) during regular tidal breathing registered by a belt system. Image reconstruction involved a raw data-based iterative algorithm (1.5-mm slice thickness, 1.0-mm z-axis increment, 5% respiratory increment), resulting in a stack of 6,700 images, which were evaluated with a 4D-viewing tool.

RESULTS

An excessive dynamic collapse of the trachea in combination with tracheobronchomalacia (TBM) of the main-stem and segmental bronchi, and a paradoxical diaphragmatic motion were demonstrated in 1 case. Moreover, we detected a saber-sheath trachea and main-stem TBM in another case. The third case showed a fixed tracheal stenosis.

CONCLUSIONS

4D-CT provides unprecedented z-axis coverage and time-resolved volumetric datasets of the whole chest. Airway instability, stenosis and paradoxical diaphragmatic motion may be assessed simultaneously, preceding interventions such as airway stabilization or lung volume reduction.

Bronchoscopic lung volume reduction

The management of obstructive lung disease, particularly emphysematous lung disease, is aggressively being pursued. The patient populations that will experience the greatest benefit with lung volume reduction are those that are the worst candidates for surgical intervention. Identifying a bronchoscopic approach that has a true impact on this patient population will be a major accomplishment in the management of patients with chronic obstructive pulmonary disease. This article highlights the work currently ongoing in the area of bronchoscopic lung volume reduction. There are tools now clinically available in some locations throughout the world, but no standardized technique exists.

The role of bronchodilator treatment in the prevention of exacerbations of COPD

Exacerbations of chronic obstructive pulmonary disease (COPD) are natural events in the progression of the disease, and are characterised by acute worsening of symptoms, especially dyspnoea. These heterogeneous events follow increased airway inflammation, often due to infection, and lead to decreased airflow and increased lung hyperinflation relative to stable COPD. Although exacerbation frequency generally increases as COPD progresses, some patients experience frequent exacerbations (≥ 2 per year) independently of disease severity. Exacerbations, especially frequent exacerbations, are associated with impaired health-related quality of life, reduced physical activity and poor disease prognosis. The cornerstone of pharmacotherapy for stable COPD is long-acting bronchodilators, including the long-acting β(2)-agonists (LABAs) and long-acting anti-muscarinic agents (LAMAs) alone or combined with inhaled corticosteroids (ICS). While ICS treatment can potentially reduce the risk of exacerbations, clinical studies have demonstrated the efficacy of LABAs and LAMAs in reducing COPD symptoms, primarily by reducing lung hyperinflation secondary to reduced airway resistance. Sustained reduction in lung hyperinflation may in turn lessen dyspnoea during an exacerbation. Indeed, recent studies suggest that bronchodilators may also reduce the incidence of, or prevent, exacerbations. Using data from recent studies, this review explores the evidence and possible mechanisms through which bronchodilators may prevent exacerbations.

The effect of lung volume reduction surgery on chronotropic incompetence

BACKGROUND

Chronotropic incompetence (CI) is a marker of poor prognosis in patients with COPD. Treatments that improve pulmonary function and exercise capacity may affect CI. Objectives are to evaluate CI before and after lung volume reduction surgery (LVRS) and determine if changes in CI are associated with changes in pulmonary function and exercise capacity.

METHODS

We performed a retrospective review of 75 patients who underwent LVRS and who had complete cardiopulmonary exercise testing and concurrent pulmonary function tests two months before and about 6 months after surgery. Additionally we evaluated 28 control patients that were randomized to medical treatment as part of the National Emphysema Treatment Trial at our center. We studied CI using the percent of predicted heart rate reserve=(heart rate peak-heart rate rest)/((208-0.7×age)-heart rate rest)×100, before and after surgery and compared it to the control group.

RESULTS

Mean percent of predicted heart rate reserve improved from 41% to 50% (p-value <0.001) after LVRS, while the control group did not change. The mean forced vital capacity and expiratory volume in 1s, peak oxygen consumption, carbon dioxide production, ventilation, tidal volume and maximal workload all improved in the surgery group, while the controls did not improve.

CONCLUSIONS

CI improves after LVRS in a population of patients with COPD. CI improvements are associated with the increases in pulmonary function and exercise capacity. This improvement is seen in a domain of known cardiopulmonary impairment prior to surgery that improves as a positive response to the therapy of LVRS.

Lung volume reduction surgery for native lung hyperinflation following single-lung transplantation for emphysema: which patients?

OBJECTIVES

Lung transplantation is an established treatment for patients with advanced emphysema. Double-lung transplantation is favoured to avoid complications following single-lung transplantation, including native lung hyperinflation. Nonetheless, single-lung transplantation continues due to limited donor organ availability. The aim of this study was to evaluate the pre-operative assessment, surgical techniques and outcomes in patients undergoing lung volume reduction surgery for native lung hyperinflation.

METHODS

Eight patients underwent lung volume reduction surgery for native lung hyperinflation between October 2008 and April 2011. Symptoms, pre-operative evaluation, peri-operative morbidity, length of stay, pulmonary function and survival were examined. The mean follow-up was 17 months.

RESULTS

Participants underwent high resolution CT and bronchoscopy with transbronchial biopsy and bronchial washings to exclude alternative causes for deterioration in pulmonary function tests. V/Q scan was performed to assess the contribution of each lung to overall function. Measurement of inspiratory airflow resistance in each lung was performed in one case. Seven patients underwent multiple wedge resections and one underwent bilobectomy. All patients survived to hospital discharge, and mean length of stay was 13.9 days. Functional improvement was demonstrated in all cases at follow-up, with a mean percentage increase of 29.3% in forced expiratory volume in one second and 21.6% in forced vital capacity. Symptomatic improvement was also reported by all patients post-operatively.

CONCLUSIONS

Lung volume reduction surgery for native lung hyperinflation is an effective treatment strategy with an acceptable level of surgical risk. Patient selection, however, remains vital. The non-anatomical multiple wedge excision technique used here was as effective as anatomical lung volume reduction surgery used in other series. With regard to pre-operative assessment, the measurement of single-lung inspiratory airflow resistance is of particular interest. We feel that this may provide an additional method of differentiating between native lung hyperinflation and obliterative bronchiolitis prior to surgery, thus improving patient selection.

Pulmonary hypertension in a stable community-based COPD population

STUDY OBJECTIVES

The etiology and prevalence of pulmonary hypertension (PH) in patients with stable chronic obstructive pulmonary disease (COPD) is uncertain. This study was done to determine the prevalence of PH in stable COPD outpatients and to evaluate the relationship between PH and indices of pulmonary function.

DESIGN

The study was a retrospective review of outpatients with COPD and PH defined as a history of cigarette smoking, pulmonary function tests (PFTs) that met GOLD criteria for airway obstruction, an echocardiogram within 6 months of PFTs, and a left ventricular ejection fraction (LVEF) >55%. Of the 159 individuals who met all inclusion criteria, 105 had a sufficient tricuspid regurgitant jet to measure systolic pulmonary artery pressure (sPAP). PH was defined as sPAP ≥36 mmHg.

MEASUREMENTS AND RESULTS

The prevalence of PH was 60% (63/105) in the study group. The mean sPAP in patients with PH was 45 ± 6 mmHg. COPD patients with PH were older (71.1 ± 11.8 vs. 63.7 ± 10.2 years, P = 0.001), had lower FEV(1)% predicted (51.8 ± 18.8 vs. 62.7 ± 20.5%, P = 0.006), a higher RV/TLC (0.55 ± 0.10 vs. 0.48 ± 0.11, P = 0.001), and a lower % predicted DL(CO) (59.6 ± 19.5% vs. 71.9 ± 24.9%, P = 0.006). Only age (P < 0.002) and prebronchodilator FEV(1)% predicted (P < 0.006) predicted PH by logistic regression analysis. No differences were observed in gender, BMI, smoking status, pack years, total lung capacity (TLC), or residual volume (RV).

CONCLUSION

PH is common in COPD. Older individuals and those with more airway obstruction are at greater risk for developing PH.

Lung transplantation and lung volume reduction surgery

Since the publication of the last edition of the Handbook of Physiology, lung transplantation has become widely available, via specialized centers, for a variety of end-stage lung diseases. Lung volume reduction surgery, a procedure for emphysema first conceptualized in the 1950s, electrified the pulmonary medicine community when it was rediscovered in the 1990s. In parallel with their technical and clinical refinement, extensive investigation has explored the unique physiology of these procedures. In the case of lung transplantation, relevant issues include the discrepant mechanical function of the donor lungs and recipient thorax, the effects of surgical denervation, acute and chronic rejection, respiratory, chest wall, and limb muscle function, and response to exercise. For lung volume reduction surgery, there have been new insights into the counterintuitive observation that lung function in severe emphysema can be improved by resecting the most diseased portions of the lungs. For both procedures, insights from physiology have fed back to clinicians to refine patient selection and to scientists to design clinical trials. This section will first provide an overview of the clinical aspects of these procedures, including patient selection, surgical techniques, complications, and outcomes. It then reviews the extensive data on lung and muscle function following transplantation and its complications. Finally, it reviews the insights from the last 15 years on the mechanisms whereby removal of lung from an emphysema patient can improve the function of the lung left behind.

A randomized study of endobronchial valves for advanced emphysema

BACKGROUND

Endobronchial valves that allow air to escape from a pulmonary lobe but not enter it can induce a reduction in lobar volume that may thereby improve lung function and exercise tolerance in patients with pulmonary hyperinflation related to advanced emphysema.

METHODS

We compared the safety and efficacy of endobronchial-valve therapy in patients with heterogeneous emphysema versus standard medical care. Efficacy end points were percent changes in the forced expiratory volume in 1 second (FEV1) and the 6-minute walk test on intention-to-treat analysis. We assessed safety on the basis of the rate of a composite of six major complications.

RESULTS

Of 321 enrolled patients, 220 were randomly assigned to receive endobronchial valves (EBV group) and 101 to receive standard medical care (control group). At 6 months, there was an increase of 4.3% in the FEV1 in the EBV group (an increase of 1.0 percentage point in the percent of the predicted value), as compared with a decrease of 2.5% in the control group (a decrease of 0.9 percentage point in the percent of the predicted value). Thus, there was a mean between-group difference of 6.8% in the FEV1 (P=0.005). Roughly similar between-group differences were observed for the 6-minute walk test. At 12 months, the rate of the complications composite was 10.3% in the EBV group versus 4.6% in the control group (P=0.17). At 90 days, in the EBV group, as compared with the control group, there were increased rates of exacerbation of chronic obstructive pulmonary disease (COPD) requiring hospitalization (7.9% vs. 1.1%, P=0.03) and hemoptysis (6.1% vs. 0%, P=0.01). The rate of pneumonia in the target lobe in the EBV group was 4.2% at 12 months. Greater radiographic evidence of emphysema heterogeneity and fissure completeness was associated with an enhanced response to treatment.

CONCLUSIONS

Endobronchial-valve treatment for advanced heterogeneous emphysema induced modest improvements in lung function, exercise tolerance, and symptoms at the cost of more frequent exacerbations of COPD, pneumonia, and hemoptysis after implantation. (Funded by Pulmonx; ClinicalTrials.gov number, NCT00129584.)

National Emphysema Treatment Trial redux: accentuating the positive

OBJECTIVE

Under the Freedom of Information Act, we obtained the follow-up data of the National Emphysema Treatment Trial (NETT) to determine the long-term outcome for "a heterogeneous distribution of emphysema with upper lobe predominance," postulated by the NETT hypothesis to be optimal candidates for lung volume reduction surgery.

METHODS

Using the NETT database, we identified patients with heterogeneous distribution of emphysema with upper lobe predominance and analyzed for the first time follow-up data for those receiving lung volume reduction surgery and those receiving medical management. Furthermore, we compared the results of the NETT reduction surgery group with a previously reported consecutive case series of 250 patients undergoing bilateral lung volume reduction surgery using similar selection criteria.

RESULTS

Of the 1218 patients enrolled, 511 (42%) conformed to the NETT hypothesis selection criteria and received the randomly assigned surgical or medical treatment (surgical = 261; medical = 250). Lung volume reduction surgery resulted in a 5-year survival benefit (70% vs 60%; P = .02). Results at 3 years compared with baseline data favored surgical reduction in terms of residual volume reduction (25% vs 2%; P < .001), University of California San Diego dyspnea score (16 vs 0 points; P < .001), and improved St George Respiratory Questionnaire quality of life score (12 points vs 0 points; P < .001). For the 513 patients with a homogeneous pattern of emphysema randomized to surgical or medical treatment, lung volume reduction surgery produced no survival advantage and very limited functional benefit.

CONCLUSIONS

Patients most likely to benefit from lung volume reduction surgery have heterogeneously distributed emphysema involving the upper lung zones predominantly. Such patients in the NETT trial had results nearly identical to those previously reported in a nonrandomized series of similar patients undergoing lung volume reduction surgery.

Interventional treatment options for advanced emphysema: imaging manifestations

Chronic obstructive pulmonary disease is a preventable and treatable disease characterized by progressive and debilitating limitations of airflow. Despite aggressive medical therapy, many patients with advanced emphysema continue to decline and exhibit disabling symptoms. Lung volume reduction surgery and lung transplantation can offer improved quality of life, enhanced exercise tolerance, and improvement in mortality rates in selected patients with advanced disease. In addition, newer bronchoscopic techniques to reduce lung volume in patients with emphysema are under development in an effort to duplicate the results of lung volume reduction surgery without significant morbidity. This article discusses the results of a variety of surgical and bronchoscopic interventions, with an emphasis upon the role of imaging.

Variations of inflammatory mediators and alpha1-antitrypsin levels after lung volume reduction surgery for emphysema

RATIONALE

In emphysema, chronic inflammation, including protease-antiprotease imbalance, is responsible for declining pulmonary function and progressive cachexia.

OBJECTIVES

To evaluate variations of inflammatory mediators and alpha(1)-antitrypsin levels after lung volume reduction surgery (LVRS) compared with respiratory rehabilitation.

METHODS

A total of 28 patients with moderate to severe emphysema, who underwent video-assisted thoracoscopic LVRS, were compared with 26 similar patients, who refused operation and followed a standardized rehabilitation program, and to a matched healthy group. Respiratory function, body composition, circulating inflammatory mediators, and alpha(1)-antitrypsin levels were evaluated before and 12 months after treatment. Gene expression levels of inflammatory mediators and protease-antiprotease were assessed in emphysematous specimens from 17 operated patients by matching to normal tissue from resection margins.

MEASUREMENTS AND MAIN RESULTS

Significant improvements were only obtained after surgery in respiratory function (FEV(1), +25.2%, P < 0.0001; residual volume [RV], -19.5%, P < 0.0001; diffusing lung capacity for carbon monoxide, +3.3%, P < 0.05) and body composition (fat-free mass, +6.5%, P < 0.01; fat mass, +11.9%, P < 0.01), with decrement of circulating inflammatory mediators (TNF-alpha, -22.2%, P < 0.001; IL-6, -24.5%, P < 0.001; IL-8, -20.0%, P < 0.001) and increment of antiprotease levels (alpha(1)-antitrypsin, +27.0%, P < 0.001). Supportive gene expression analysis demonstrated active inflammation and protease hyperactivity in the resected emphysematous tissue. Reduction of TNF-alpha and IL-6 and increment of alpha(1)-antitrypsin levels significantly correlated with reduction of RV (P = 0.03, P = 0.009, and P = 0.001, respectively), and partially with increment of fat-free mass (P = 0.03, P = 0.02, and P = 0.09, respectively).

CONCLUSIONS

LVRS significantly reduced circulating inflammatory mediators and increased antiprotease levels over respiratory rehabilitation, also improving respiratory function and nutritional status. Correlations of inflammatory mediators and antiprotease levels with RV and, partly, with body composition suggest that elimination of inflammatory emphysematous tissue may explain clinical improvements after surgery.

[Surgical management of COPD distension]

INTRODUCTION

The impressive results seen when giant and compressing lung bullae are resected has inspired pneumonologists and thoracic surgeons to consider the possibility of applying a similar approach to the treatment of respiratory failure due to chronic obstructive pulmonary disease (COPD).

STATE OF THE ART

The major problem with this surgical indication lies in our ability to understand fully the pathophysiology of lesions and thus identify which emphysematous patients will have a response most similar to that achieved in purely bullous disease.

PERSPECTIVES

At the present time consideration should be given as to whether surgery is the only means of reducing pulmonary distension. Indeed, as endoscopic alternatives develop could they reproduce its beneficial effects and what would be their place compared to the surgery?

CONCLUSIONS

While waiting the development of these innovations, if the selection of the candidates is correct, the surgical treatment of lung hyperinflation can temporarily improve the quality of life of these patients by decreasing their dyspnea and increasing their exercise tolerance.

Physiological and computed tomographic predictors of outcome from lung volume reduction surgery

RATIONALE

Previous investigations have identified several potential predictors of outcomes from lung volume reduction surgery (LVRS). A concern regarding these studies has been their small sample size, which may limit generalizability. We therefore sought to examine radiographic and physiologic predictors of surgical outcomes in a large, multicenter clinical investigation, the National Emphysema Treatment Trial.

OBJECTIVES

To identify objective radiographic and physiological indices of lung disease that have prognostic value in subjects with chronic obstructive pulmonary disease being evaluated for LVRS.

METHODS

A subset of the subjects undergoing LVRS in the National Emphysema Treatment Trial underwent preoperative high-resolution computed tomographic (CT) scanning of the chest and measures of static lung recoil at total lung capacity (SRtlc) and inspiratory resistance (Ri). The relationship between CT measures of emphysema, the ratio of upper to lower zone emphysema, CT measures of airway disease, SRtlc, Ri, the ratio of residual volume to total lung capacity (RV/TLC), and both 6-month postoperative changes in FEV(1) and maximal exercise capacity were assessed.

MEASUREMENTS AND MAIN RESULTS

Physiological measures of lung elastic recoil and inspiratory resistance were not correlated with improvement in either the FEV(1) (R = -0.03, P = 0.78 and R = -0.17, P = 0.16, respectively) or maximal exercise capacity (R = -0.02, P = 0.83 and R = 0.08, P = 0.53, respectively). The RV/TLC ratio and CT measures of emphysema and its upper to lower zone ratio were only weakly predictive of postoperative changes in both the FEV(1) (R = 0.11, P = 0.01; R = 0.2, P < 0.0001; and R = 0.23, P < 0.0001, respectively) and maximal exercise capacity (R = 0.17, P = 0.0001; R = 0.15, P = 0.002; and R = 0.15, P = 0.002, respectively). CT assessments of airway disease were not predictive of change in FEV(1) or exercise capacity in this cohort.

CONCLUSIONS

The RV/TLC ratio and CT measures of emphysema and its distribution are weak but statistically significant predictors of outcome after LVRS.

Lung volume reduction surgery in nonheterogeneous emphysema

Patients with a homogeneous type of emphysema have been excluded a priori from LVRS in many centers because of the fear of removing parenchyma, which potentially contributes to gas exchange, and because the observation that heterogeneity of emphysema is a predictor of functional improvement. It is obvious that resection of functionless tissue, such as in heterogeneous emphysema with bullae, can be advised to the patient with a relative low risk. However, as the main positive effect of LVRS is its improvement on respiratory mechanics, it is not surprising that well-selected patients with homogeneous emphysema also benefit from surgery. Their selection has to be done cautiously. It is crucial to exclude patients with a very low functional reserve, such as with diffusing capacity below 20% predicted or with pulmonary hypertension, and with extreme parenchymal loss (vanished lungs) on CT from LVRS. Additionally, cofactors which may potentially interfere with a smooth postoperative course, such as previous recurrent infections, extensive scarring of the lungs, or previous surgery, have to be taken into consideration. When respecting these caveats, LVRS in patients with complete homogeneous emphysema provides a comparable symptomatic and almost the same functional improvement as in patients with heterogeneous emphysema. Although the perioperative mortality is low, patients with homogeneous emphysema have a slightly reduced long-term survival without lung transplantation compared with patients with heterogeneous emphysema. Based on our own experience, we conclude that LVRS can be recommended to selected symptomatic patients with advanced homogenous emphysema associated with severe hyperinflation, if diffusing capacity is not below 20% of predicted values and if the CT scan does not show aspects of vanished lungs.

Effects of lung volume reduction surgery on gas exchange and breathing pattern during maximum exercise

BACKGROUND

The National Emphysema Treatment Trial studied lung volume reduction surgery (LVRS) for its effects on gas exchange, breathing pattern, and dyspnea during exercise in severe emphysema.

METHODS

Exercise testing was performed at baseline, and 6, 12, and 24 months. Minute ventilation (Ve), tidal volume (Vt), carbon dioxide output (Vco(2)), dyspnea rating, and workload were recorded at rest, 3 min of unloaded pedaling, and maximum exercise. Pao(2), Paco(2), pH, fraction of expired carbon dioxide, and bicarbonate were also collected in some subjects at these time points and each minute of testing. There were 1,218 patients enrolled in the study (mean [+/- SD] age, 66.6 +/- 6.1 years; mean, 61%; mean FEV(1), 0.77 +/- 0.24 L), with 238 patients participating in this substudy (mean age, 66.1 +/- 6.8 years; mean, 67%; mean FEV(1), 0.78 +/- 0.25 L).

RESULTS

At 6 months, LVRS patients had higher maximum Ve (32.8 vs 29.6 L/min, respectively; p = 0.001), Vco(2), (0.923 vs 0.820 L/min, respectively; p = 0.0003), Vt (1.18 vs 1.07 L, respectively; p = 0.001), heart rate (124 vs 121 beats/min, respectively; p = 0.02), and workload (49.3 vs 45.1 W, respectively; p = 0.04), but less breathlessness (as measured by Borg dyspnea scale score) [4.4 vs 5.2, respectively; p = 0.0001] and exercise ventilatory limitation (49.5% vs 71.9%, respectively; p = 0.001) than medical patients. LVRS patients with upper-lobe emphysema showed a downward shift in Paco(2) vs Vco(2) (p = 0.001). During exercise, LVRS patients breathed slower and deeper at 6 months (p = 0.01) and 12 months (p = 0.006), with reduced dead space at 6 months (p = 0.007) and 24 months (p = 0.006). Twelve months after patients underwent LVRS, dyspnea was less in patients with upper-lobe emphysema (p = 0.001) and non-upper-lobe emphysema (p = 0.007).

CONCLUSION

During exercise following LVRS, patients with severe emphysema improve carbon dioxide elimination and dead space, breathe slower and deeper, and report less dyspnea.

Cost-effectiveness of lung volume reduction surgery

Lung volume reduction surgery (LVRS) is a costly procedure that can improve quality and quantity of life. Given the prevalence of emphysema, the costs involved with its management, and resource constraints on all health care delivery systems, evaluating the cost-effectiveness of LVRS is important. In this article, we describe the purposes and principles of cost-effectiveness analysis and how those principles were applied in evaluating LVRS. We present the results of the cost-effectiveness analysis that was conducted alongside the National Emphysema Treatment Trial and other economic studies of LVRS and discuss how these should be interpreted in the context of current reimbursement guidelines.

Physiologic basis for improved pulmonary function after lung volume reduction

It is not readily apparent how pulmonary function could be improved by resecting portions of the lung in patients with emphysema. In emphysema, elevation in residual volume relative to total lung capacity reduces forced expiratory volumes, increases inspiratory effort, and impairs inspiratory muscle mechanics. Lung volume reduction surgery (LVRS) better matches the size of the lungs to the size of the thorax containing them. This restores forced expiratory volumes and the mechanical advantage of the inspiratory muscles. In patients with heterogeneous emphysema, LVRS may also allow space occupied by cysts to be reclaimed by more normal lung. Newer, bronchoscopic methods for lung volume reduction seek to achieve similar ends by causing localized atelectasis, but may be hindered by the low collateral resistance of emphysematous lung. Understanding of the mechanisms of improved function after LVRS can help select patients more likely to benefit from this approach.

Cardiac disease in chronic obstructive pulmonary disease

The cardiac manifestations of chronic obstructive pulmonary disease (COPD) are numerous. Impairments of right ventricular dysfunction and pulmonary vascular disease are well known to complicate the clinical course of COPD and correlate inversely with survival. The pathogenesis of pulmonary vascular disease in COPD is likely multifactorial and related to alterations in gas exchange and vascular biology, as well as structural changes of the pulmonary vasculature and mechanical factors. Several modalities currently exist for the assessment of pulmonary vascular disease in COPD, but right heart catheterization remains the gold standard. Although no specific therapy other than oxygen has been generally accepted for the treatment of pulmonary hypertension in this population, there has been renewed interest in specific pulmonary vasodilators. The coexistence of COPD and coronary artery disease occurs frequently. This association is likely related to shared risk factors as well as similar pathogenic mechanisms, such as systemic inflammation. Management strategies for the care of patients with COPD and coronary artery disease are similar to those without COPD, but care must be given to address their respiratory limitations. Arrhythmias occur frequently in patients with COPD, but are rarely fatal and can generally be treated medically. Use of beta-blockers in the management of cardiac disease, while a theoretical concern in patients with increased airway resistance, is generally safe with the use of cardioselective agents.

Bronchoscopic lung volume reduction in severe emphysema

Lung volume reduction surgery (LVRS) produces physiological, symptomatic, and survival benefits in selected patients with advanced emphysema. Because it is associated with significant morbidity, mortality, and cost, nonsurgical alternatives for achieving volume reduction have been developed. Three bronchoscopic lung volume reduction (BLVR) approaches have shown promise and reached later-stage clinical trials. These include the following: (1) placement of endobronchial one-way valves designed to promote atelectasis by blocking inspiratory flow; (2) formation of airway bypass tracts using a radiofrequency catheter designed to facilitate emptying of damaged lung regions with long expiratory times; and (3) instillation of biological adhesives designed to collapse and remodel hyperinflated lung. The limited clinical data currently available suggest that all three techniques are reasonably safe. However, efficacy signals have been substantially smaller and less durable than those observed after LVRS. Studies to optimize patient selection, refine treatment strategies, characterize procedural safety, elucidate mechanisms of action, and characterize short- and longer-term effectiveness of these approaches are ongoing. Results will be available over the next few years and will determine whether BLVR represents a safe and effective alternative to LVRS.

New concepts in the pathobiology of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by an abnormal persistent inflammatory response to cigarette smoke. This noxious insult leads to emphysema and airway remodeling, manifested by squamous and mucous metaplasia of the epithelium, smooth muscle hypertrophy, and airway wall fibrosis. These pathologic abnormalities interact synergistically to cause progressive airflow obstruction. Although it has been accepted that the spectrum of COPD is vast, the reasons for the development of different phenotypes from the same exposure to cigarette smoke have not been determined. Furthermore, it is becoming increasingly clear that airways disease and emphysema often coexist in many patients, even with a clear clinical phenotype of either emphysema or chronic bronchitis. Recent studies have focused on the nature of the inflammatory response to cigarette smoke, the inflammatory cell lines responsible for COPD pathogenesis, and new biomarkers for disease activity and progression. New cytokines are being discovered, and the complex interactions among them are being unraveled. The inflammatory biomarker that has received the most attention is C-reactive protein, but new ones that have caught our attention are interleukin (IL)-6, tumor necrosis factor-alpha, IL-8, and IL-10. Further research should focus on how these new concepts in lung inflammation interact to cause the various aspects of COPD pathology.

Tiotropium bromide

Therapy with bronchodilators forms the pharmacologic foundation of the treatment of patients with COPD. Bronchodilators can significantly lessen dyspnea, increase airflow, improve quality of life, and enhance exercise performance. While bronchodilators decrease airway resistance and lessen dynamic hyperinflation in patients with COPD, they have not been shown to alter the rate of decline in FEV₁ over time, or improve patient survival. Fairly recently, a long-acting, once-daily anticholinergic medication, tiotropium bromide, has been developed which may improve symptom management in COPD patients. This paper reviews anticholinergic pharmacologic therapy for patients with COPD focusing on tiotropium bromide, and discusses treatment strategies based on disease stage. It is important to recognize that while bronchodilators improve symptoms, a multimodality treatment approach including respiratory and rehabilitative therapy, nutrition services, psychosocial counseling, and surgical care, is often necessary for the best possible care of patients with COPD.

Lungenparenchymerkrankungen

Das Lungenemphysem ist pathologisch-anatomisch definiert. Man versteht darunter eine irreversible abnorme Erweiterung der lufthaltigen Räume distal der Bronchioli terminales, die mit einer Destruktion der Alveolarsepten einhergeht. Neben der chronischen Bronchitis und der Bronchiolitis ist das Lungenemphysem eine der morphologischen Komponenten der chronisch-obstruktiven Lungenkrankheit (COPD). Bei fortgeschrittenen Formen der COPD besteht mit Regelmäßiigkeit ein erhebliches Lungenemphysem.

The effect of lung volume reduction surgery on chronic obstructive pulmonary disease exacerbations

RATIONALE

Lung volume reduction surgery (LVRS) has been demonstrated to provide a functional and mortality benefit to a select group of subjects with chronic obstructive pulmonary disease (COPD). The effect of LVRS on COPD exacerbations has not been as extensively studied, and whether improvement in postoperative lung function alters the risk of disease exacerbations is not known.

OBJECTIVES

To examine the effect, and mechanism of potential benefit, of LVRS on COPD exacerbations by comparing the medical and surgical cohorts of the National Emphysema Treatment Trial (NETT).

METHODS

A COPD exacerbation was defined using Centers for Medicare and Medicaid Services data and International Classification of Diseases, Ninth Revision, discharge diagnosis.

MEASUREMENTS AND MAIN RESULTS

There was no difference in exacerbation rate or time to first exacerbation between the medical and surgical cohorts during the year before study randomization (P = 0.58 and 0.85, respectively). Postrandomization, the surgical cohort experienced an approximate 30% reduction in exacerbation frequency (P = 0.0005). This effect was greatest in those subjects with the largest postoperative improvement in FEV(1) (P = 0.04) when controlling for changes in other spirometric measures of lung function, lung capacities, and room air arterial blood gas tensions. Finally, LVRS increased the time to first exacerbation in both those subjects with and those without a prior history of exacerbations (P = 0.0002 and P < 0.0001, respectively).

CONCLUSIONS

LVRS reduces the frequency of COPD exacerbations and increases the time to first exacerbation. One explanation for this benefit may be the postoperative improvement in lung function.

Lung elastic recoil does not correlate with pulmonary hemodynamics in severe emphysema

BACKGROUND

It has been postulated that right ventricular (RV) function may improve after lung volume reduction surgery (LVRS) for severe emphysema due to improvement in lung elastic recoil. Improved lung elastic recoil after LVRS is hypothesized to "tether" open extraalveolar vessels, thereby leading to a decrease in pulmonary vascular resistance (PVR) and improved RV function. Whether a relationship exists between static elastic lung recoil and pulmonary hemodynamics in severe emphysema, however, is unknown.

METHODS

We prospectively studied 67 patients with severe emphysema (32 women; mean age, 65.3+/-6.6 years [SD]; mean FEV1, 0.79+/-0.25 L) who had hyperinflation (total lung capacity [TLC], 122.5+/-12.3% of predicted) and gas trapping (residual volume, 209.1+/-41.1% of predicted), and were referred to the National Emphysema Treatment Trial. Lung elastic recoil was measured both at TLC (coefficient of retraction [CR]) and at functional reserve capacity (CR at functional residual capacity [CRfrc]) in each patient.

RESULTS

CR and CRfrc values were 1.3+/-0.6 cm H2O/L and 0.61+/-0.5 cm H2O/L, respectively. Hemodynamic measurements revealed a pulmonary artery (PA) systolic pressure of 35.9+/-8.9 mm Hg, mean PA pressure of 24.8+/-5.6 mm Hg, and PVR of 174+/-102 dyne*s*cm(-5). No significant correlations were found between CR and PVR (R=-0.046, p=0.71), PA systolic pressure (R=0.005, p=0.97), or mean PA pressure (R=-0.028, p=0.82). Additionally, no significant correlations were found between CRfrc and PVR (R=-0.002, p=0.99), PA systolic pressure (R=-0.062, p=0.62), or mean PA pressure (R=-0.041, p=0.74).

CONCLUSIONS

We conclude there is no correlation between lung elastic recoil and pulmonary hemodynamics in severe emphysema, suggesting that elastic lung recoil is not an important determinant of secondary pulmonary hypertension in this group. Registered with www. clinicaltrials.gov, #NCT00000606.

Update in Surgical Therapy for Chronic Obstructive Pulmonary Disease

Bullectomy for giant bullae, lung volume reduction surgery, and lung transplantation are three surgical therapies that may benefit highly selected patients with advanced chronic obstructive pulmonary disease. In this article, each procedure is reviewed, with an emphasis on guidelines for patient selection and clinical outcomes for the practicing pulmonologist. Recent results from the National Emphysema Treatment Trial, updated International Society for Heart and Lung Transplantation Registry data, and revised guidelines for patient selection for lung transplantation are discussed.

Design of the Endobronchial Valve for Emphysema Palliation Trial (VENT): a non-surgical method of lung volume reduction

Background

Lung volume reduction surgery is effective at improving lung function, quality of life, and mortality in carefully selected individuals with advanced emphysema. Recently, less invasive bronchoscopic approaches have been designed to utilize these principles while avoiding the associated perioperative risks. The Endobronchial Valve for Emphysema PalliatioN Trial (VENT) posits that occlusion of a single pulmonary lobe through bronchoscopically placed Zephyr^® endobronchial valves will effect significant improvements in lung function and exercise tolerance with an acceptable risk profile in advanced emphysema.

Methods

The trial design posted on Clinical trials.gov, on August 10, 2005 proposed an enrollment of 270 subjects. Inclusion criteria included: diagnosis of emphysema with forced expiratory volume in one second (FEV₁) < 45% of predicted, hyperinflation (total lung capacity measured by body plethysmography > 100%; residual volume > 150% predicted), and heterogeneous emphysema defined using a quantitative chest computed tomography algorithm. Following standardized pulmonary rehabilitation, patients were randomized 2:1 to receive unilateral lobar placement of endobronchial valves plus optimal medical management or optimal medical management alone. The co-primary endpoint was the mean percent change in FEV₁ and six minute walk distance at 180 days. Secondary end-points included mean percent change in St. George's Respiratory Questionnaire score and the mean absolute changes in the maximal work load measured by cycle ergometry, dyspnea (mMRC) score, and total oxygen use per day. Per patient response rates in clinically significant improvement/maintenance of FEV₁ and six minute walk distance and technical success rates of valve placement were recorded. Apriori response predictors based on quantitative CT and lung physiology were defined.

Conclusion

If endobronchial valves improve FEV₁ and health status with an acceptable safety profile in advanced emphysema, they would offer a novel intervention for this progressive and debilitating disease.

Trial Registration

ClinicalTrials.gov: NCT00129584

Effect of lung volume reduction surgery on resting pulmonary hemodynamics in severe emphysema

RATIONALE

To determine the effect of medical treatment versus lung volume reduction surgery (LVRS) on pulmonary hemodynamics.

METHODS

Three clinical centers of the National Emphysema Treatment Trial (NETT) screened patients for additional inclusion into a cardiovascular (CV) substudy. Demographics were determined, and lung function testing, six-minute-walk distance, and maximum cardiopulmonary exercise testing were done at baseline and 6 months after medical therapy or LVRS. CV substudy patients underwent right heart catheterization at rest prerandomization (baseline) and 6 months after treatment.

MEASUREMENTS AND MAIN RESULTS

A total of 110 of the 163 patients evaluated for the CV substudy were randomized in NETT (53 were ineligible), 54 to medical treatment and 56 to LVRS. Fifty-five of these patients had both baseline and repeat right heart catheterization 6 months postrandomization. Baseline demographics and lung function data revealed CV substudy patients to be similar to the remaining 1,163 randomized NETT patients in terms of age, sex, FEV(1), residual volume, diffusion capacity of carbon monoxide, Pa(O(2)), Pa(CO(2)), and six-minute-walk distance. CV substudy patients had moderate pulmonary hypertension at rest (Ppa, 24.8 +/- 4.9 mm Hg); baseline hemodynamic measurements were similar across groups. Changes from baseline pressures to 6 months post-treatment were similar across treatment groups, except for a smaller change in pulmonary capillary wedge pressure at end-expiration post-LVRS compared with medical treatment (-1.8 vs. 3.5 mm Hg, p = 0.04).

CONCLUSIONS

In comparison to medical therapy, LVRS was not associated with an increase in pulmonary artery pressures.

Reduced intrathoracic blood volume and left and right ventricular dimensions in patients with severe emphysema: an MRI study

BACKGROUND

Left ventricular (LV) filling is impaired in patients with severe emphysema manifesting in small end-diastolic dimensions. We hypothesized that the hyperinflated lungs of these patients with high intrinsic positive end-expiratory pressure will decrease intrathoracic blood volume (ITBV) and ventricular preload. We therefore measured ITBV, and LV and right ventricular (RV) dimensions and function using MRI techniques in patients with severe emphysema.

METHODS

Patients with severe emphysema (n = 13) and matched healthy volunteers (n = 11) were included. The magnetic resonance (MR) examination consisted of three parts: (1) evaluation of RV and LV dimensions and function and interventricular septum curvature using cine MRI; (2) quantification of aortic flow using MR phase velocity mapping; and (3) calculation of the cardiopulmonary peak transit time (PTT) from the pulmonary artery to the ascending aorta using contrast-enhanced, time-resolved, two-dimensional MR angiography.

RESULTS

There were no differences between the groups regarding age, height, or weight. In the emphysema patients, ITBV index (- 35%), LV end-diastolic volume index (LVEDVI) [- 21%], RV end-diastolic volume index (- 20%), cardiac index (- 22%), and stroke volume index (SVI) [- 40%] were lower compared to control subjects. LV and RV end-systolic volumes, LV wall mass, septal curvature, and PTT did not differ between the groups. LVEDVI (r = 0.83) as well as SVI (r = 0.82) correlated closely to ITBV index. SVI correlated closely to LVEDVI (r = 0.84).

CONCLUSIONS

LV and RV performance is impaired in patients with severe emphysema because of small end-diastolic dimensions. One possible explanation for the decreased biventricular preload in these patients is intrathoracic hypovolemia caused by hyperinflated lungs.

Left ventricular performance and dimensions in patients with severe emphysema

BACKGROUND

Concomitant heart dysfunction during the course of chronic obstructive pulmonary disease is well recognized. The prevailing view is that mainly the right side of the heart is involved. We evaluated left ventricular (LV) function and dimensions in patients with severe emphysema.

METHODS

Patients with severe emphysema undergoing lung volume reduction surgery were studied after anesthesia induction (n = 10). Non-emphysematous patients scheduled for lobectomy served as controls (n = 10). LV dimensions were measured with patients in the supine position by transesophageal two-dimensional echocardiography and systemic hemodynamics by a pulmonary artery thermodilution catheter, before and during central blood volume expansion by passive leg elevation.

RESULTS

Baseline cardiac index (-25%), stroke volume index (SVI, -32%) stroke work index (-34%) and LV end-diastolic area index (EDAI, -33%) were significantly (P < 0.001) lower in the emphysema group. Passive leg elevation increased SVI and LV area ejection fraction more in the emphysema group than in controls (P < 0.05). The DeltaSVI/Delta pulmonary capillary wedge pressure and the DeltaSVI/DeltaEDAI relationships were significantly (P < 0.05) higher in the emphysema group compared to controls (2.2 +/- 0.71 vs 0.6 +/- 0.2 mL/mm Hg x m2 and 5.8 +/- 0.89 vs 2.8 +/- 0.8 mL/cm2 x m2, respectively). Preload-recruitable stroke work (Deltastroke work index/DeltaEDAI), a load-independent index of systolic LV function, did not differ between the two groups.

CONCLUSION

The LV in patients with severe emphysema is hypovolemic, and operates on a steeper portion of the LV function curve, while indices of systolic function are not significantly impaired compared to non-emphysematous controls.

The clinical importance of dynamic lung hyperinflation in COPD

Lung hyperinflation commonly accompanies expiratory flow-limitation in patients with Chronic Obstructive Pulmonary Disease (COPD) and contributes importantly to dyspnea and activity limitation. It is not surprising, therefore, that lung hyperinflation has become an important therapeutic target in symptomatic COPD patients. There is increasing evidence that acute dynamic increases in lung hyperinflation, under conditions of worsening expiratory flow-limitation and increased ventilatory demand (or both) can seriously stress cardiopulmonary reserves, particularly in patients with more advanced disease. Our understanding of the physiological mechanisms of dynamic lung hyperinflation during both physical activity and exacerbations in COPD continues to grow, together with an appreciation of its serious negative mechanical and sensory consequences. In this review, we will discuss the basic pathophysiology of COPD during rest, exercise and exacerbation so as to better understand how this can be pharmacologically manipulated for the patient's benefit. Finally, we will review current concepts of the mechanisms of symptom relief and improved exercise endurance following pharmacological lung volume reduction.

Lung volume reduction surgery

Lung volume reduction surgery (LVRS) has been widely studied and has been available for the treatment of advanced emphysema for 10 years. This paper reviews some of the historical attempts at surgical treatment of emphysema, the physiology of LVRS, and the modern data on patient selection, risks, and benefits. Data from the National Emphysema Treatment Trial are presented in the context of the large body of case series and smaller randomized trials that have preceded that study. Future technologies of bronchoscopic lung volume reduction are also discussed.